Rodolfo Dirzo

Stanford University | SU · Department of Biology

Climate change threatens biodiversity as populations can persist if they migrate or adapt to the rapidly changing conditions of the Anthropocene. However, the metabolic mechanisms underlying plant population persistence under the long‐term trends of increasing temperature and drought remain unclear. Here, we investigate the persistence and adaptati...

The spatial configuration and management of agricultural and other land-use practices can affect ecological assemblages, but how resident and migratory species respond to land uses is not well known, hindering our understanding of the effects of land use on biodiversity. Here, we compare alpha and beta diversity and ecosystem functioning for reside...

Background and Aims Anthropogenic disturbances are causing a co-occurring increase in biotic (ungulate herbivory) and abiotic (drought) stressors, threatening plant reproduction in oak-dominated ecosystems. However, we wonder whether herbivory could compensate for the adverse impact of drought by reducing evapotranspiration. Thus, we investigate th...

Climate change threatens biodiversity as populations can persist if they migrate or adapt to the rapidly changing conditions of the Anthropocene. However, little is known about the persistence of plant populations under the long-term trends of increasing temperature and drought. We explore whether historical populations of yarrow ( Achillea millefo...

Ambitious biodiversity goals to protect 30% or more of the Earth’s surface by 2030 (30x30) require strategic near-term targets. To define areas that must be protected to prevent the most likely and imminent extinctions, we propose Conservation Imperatives—16,825 unprotected sites spanning ~164 Mha of the terrestrial realm that harbor rare and threa...

Cover: A pasture photographed in Lapinha da Serra, Santana do Riacho, Minas Gerais, Brazil. In a Viewpoint in this issue, Cássio Cardoso Pereira and colleagues argue that efforts to increase carbon sequestration by planting trees in such pastures constitutes a common but serious mistake, because such planting would fail to restore the pasture its n...

The focus on removing carbon dioxide from the atmosphere reflects increased public attention to climate change that potentially comes at the expense of other biodiversity challenges. This asymmetry between environmental agendas harms not only biodiversity but also climate-change mitigation because environmental issues are inexorably intertwined. Cl...

Species‐specific differences in nutrient acquisition strategies allow for complementary use of resources among plants in mixtures, which may be further shaped by mycorrhizal associations. However, empirical evidence of this potential role of mycorrhizae is scarce, particularly for tree communities. We investigated the impact of tree species richnes...

Livestock overgrazing causes environmental degradation, species invasion, biodiversity loss, and productivity decline, with profound consequences for ecological sustainability and human livelihoods. Habitat protection can mitigate such impacts, but we know little about how the long‐term recovery of plant communities from livestock overgrazing depen...

Ambitious biodiversity goals to protect 30% or more of the Earth’s surface by 2030 (30x30) require strategic near-term targets. To define areas that must be protected to prevent the most likely and imminent extinctions, we propose Conservation Imperatives—16,825 unprotected sites harboring rare and threatened species and spanning ~164 Mha of the te...

Rodents thrive across various terrestrial ecosystems due to their adaptability and diverse traits. They also serve as hosts for numerous pathogens, some with significant public health implications like Hanta Virus, Machupo, Leptospira, Lyme Disease, and plague. However, our knowledge of their role in disease transmission remains geographically limi...

The world is facing a major pulse of ecological and social changes that may favor the risk of zoonotic outbreaks. Such risk facilitation may occur through the modification of the host’s community diversity and structure, leading to an increase in pathogen reservoirs and the contact rate between these reservoirs and humans. Here, we examined whether...

Protected areas are of paramount relevance to conserving wildlife and ecosystem contributions to people. Yet, their conservation success is increasingly threatened by human activities including habitat loss, climate change, pollution, and species overexploitation. Thus, understanding the underlying and proximate drivers of anthropogenic threats is...

Species-specific differences in nutrient acquisition strategies allow for complementary use of resources among plants in mixtures, which may be further shaped by mycorrhizal associations. However, empirical evidence of these relationships is scarce, particularly for tree communities. We investigated the impact of tree species richness and mycorrhiz...

Within biodiversity‐ecosystem function research, a major outstanding question is how herbivory, a critical ecosystem function at the base of the food web, changes along gradients of plant biodiversity. Neighbourhood‐level associational effects are hypothesised to be a strong driver of biodiversity‐herbivory relationships, but we lack a successful f...

Habitat loss and fragmentation threaten population persistence because they affect the ability of individuals to disperse between remaining patches of good-quality habitat and reduce refuge areas for populations. In cougars (Puma concolor), males are predominantly dispersers while females tend to be more philopatric. To examine the dispersal abilit...

Habitat loss and fragmentation threaten population persistence because they affect the individuals’ ability to disperse between remaining habitat patches and reduce areas of refuge for populations. In cougars ( Puma concolor ), males are predominantly dispersers while females tend to be philopatric. To examine cougar philopatry and dispersal abilit...

Habitat loss due to land use change is recognized as one of the major drivers of contemporary defaunation. In this chapter, we examine tropical land mammal defaunation in Mexico from the perspective of changes in the natural land cover that represents the distribution range of a large sample (N = 252) of mammalian species. Based on a co-inertia ana...

Climate is a major extrinsic factor affecting the population dynamics of many organisms. The Broad-Scale Climate Hypothesis (BSCH) was proposed by Elton to explain the large-scale synchronous population cycles of animals, but the extent of support and whether it differs among taxa and geographical regions is unclear. We reviewed publications examin...

Lowland tropical rainforests harbor the most diverse plant communities in the world, but the herbaceous plants of the understory are often overlooked. To address this knowledge gap, we asked to what extent the understory herbaceous community contributes to the species richness and phylogenetic diversity of plant communities by surveying a neotropic...

Humanity has triggered the sixth mass extinction episode since the beginning of the Phanerozoic. The complexity of this extinction crisis is centred on the intersection of two complex adaptive systems: human culture and ecosystem functioning, although the significance of this intersection is not properly appreciated. Human beings are part of biodiv...

Mutualistic interactions are regulated by plant and animal traits, including animal body size and population density. In seed dispersal networks, frugivore body size determines the interaction outcome, and species population density determines interaction probability through encounter rates. To date, most studies examining the relative role of body...

This cover image is based on the paper: A review of philopatry and dispersal in felids living in an anthropised world by de Oliveira et al. (2021). Cover image description: male cougar Puma concolor treed by dogs in a rural property in Araguari, Minas Gerais, Brazil, 2010. Cougars and other felids are polygamous mammals that show male-biased dispe...

Emerging infectious diseases are one of the greatest public health challenges. Approximately three-quarters of these diseases are of animal origin. These diseases include classical zoonoses maintained in humans only via transmission from other vertebrates (e.g., rabies) and those initiated by a successful one-off zoonotic event (host-switch) in con...

Predator–prey interactions shape ecosystems and can help maintain biodiversity. However, for many of the earth's most biodiverse and abundant organisms, including terrestrial arthropods, these interactions are difficult or impossible to observe directly with traditional approaches. Based on previous theory, it is likely that predator–prey interacti...

Ecosystem restoration is one of the most promising strategies for conservation in the Anthropocene. Within ecosystems, plant-animal interactions are critical to their functioning, biodiversity and to restoration success. However, there is no systematic assessment of such interactions across restoration efforts. We reviewed 127 articles that examine...

Typically, males of polygamous mammals are responsible for population connectivity and gene flow via dispersal, whereas females, showing stronger philopatry, strengthen local population stability and growth. These expectations can be disrupted by human disturbances; however, this possibility has been poorly examined in wide-ranging mammals that are...

Human-mediated changes to natural ecosystems have consequences for both ecosystem and human health. Historically, efforts to preserve or restore 'biodiversity' can seem to be in opposition to human interests. However, the integration of biodiversity conservation and public health has gained significant traction in recent years, and new efforts to i...

Seed hoarding by rodents plays a significant role in shaping mutualistic or predatory interactions between tree and rodent species in forest ecosystems. However, it is still challenging to identify the seed-rodent interaction at individual level so as to reveal the differences in mutualistic or predatory interactions between seeds and rodents due t...

In their comment on our paper “Underestimating the challenges of avoiding a ghastly future” (Bradshaw et al., 2021), Bluwstein et al. (2021) attempt to contravene our exposé of the enormous challenges facing the entire human population from a rapidly degrading global environment. While we broadly agree with the need for multi-disciplinary solutions...

Significance Herbivore attack on plants is known to elicit defensive responses. Such environmentally induced responses can also be expressed by the offspring of attacked plants via DNA methylation—an epigenetic response—but little is known about if and how epigenetic induction varies with plant ontogeny (e.g., seedlings, reproductive plants). Here,...

Scattered oaks in traditional silvopastoral systems (i.e., “dehesas”) provide important ecological services. However, livestock intensification applied to these systems over the last century has affected the architecture of young oak plants. This unsuitable rangeland management practice jeopardizes the long-term system sustainability. Here we exami...

Galls are abnormal outgrowths on the external tissues of plants caused by a restricted group of organisms. In this study, we surveyed the incidence and diversity of galling structures in sympatric oak species of a biological preserve (Jasper Ridge Biological Preserve, NC, USA). We also measured different physiological parameters (SLA-specific leaf...

Background: Tropical rain forests have been impacted by land use change, leading to major deforestation and fragmentation. Understanding how fragmentation impacts plant communities is central for tropical conservation. Questions: i) How does species richness vary across a range of fragment sizes, and does it vary with plant size-structure? ii) how...

We report three major and confronting environmental issues that have received little attention and require urgent action. First, we review the evidence that future environmental conditions will be far more dangerous than currently believed. The scale of the threats to the biosphere and all its lifeforms — including humanity — is in fact so great th...

Invasive rodent eradications are frequently undertaken to curb island biodiversity loss. However, the breadth of rodents' ecological impact, even after eradication, is not always fully recognized. For example, the most widespread invasive rodent, the black rat (Rattus rattus), while omnivorous, eats predominantly seeds and fruit. Yet, the effects o...

Question Worldwide, mixed oak woodlands regenerate poorly due to different anthropogenic impacts. Our question is whether spatial distribution (regeneration microsite) of oak recruits is determined by different biotic and abiotic stress agents and whether recruits of co‐occurring oak species may respond differently to each source of stress. Locati...

Species interaction networks, which govern the maintenance of biodiversity and ecosystem processes within ecological communities, are being rapidly altered by anthropogenic activities worldwide. Studies on the response of species interaction networks to anthropogenic disturbance have almost exclusively focused on one interaction type at a time, suc...

In this chapter we examine how the current patterns of anthropogenic impact on biodiversity are engendering a pulse of animal life loss – defaunation – with emphasis on the decline and massive extinction of populations of mammals. Given that many species of this group operate as herbivores and, due to their local abundance in some regions and ecosy...

Determining linkage rules that govern the formation of species interactions is a critical goal of ecologists, especially considering that biodiversity, species interactions, and the ecosystem processes they maintain are changing at rapid rate worldwide. Species traits and abundance play a role in determining plant-pollinator interactions, but we il...

Within ecological communities, species engage in myriad interaction types, yet empirical examples of hybrid species interaction networks composed of multiple types of interactions are still scarce. A key knowledge gap is understanding how the structure and stability of such hybrid networks are affected by anthropogenic disturbance. Using 15,169 int...

The sustainability and efficiency of ecotourism regarding biodiversity conservation are under constant scrutiny and often dismissed based on negative effects arising from other types of nature-based tourism. Our study assess the impacts of infrastructure, human activity, and environmental factors on medium-large ground terrestrial species within th...

Seed predators sometimes inflict non‐lethal seed damage. We asked whether seed size modulates the location of insect seed damage and examined whether location‐specific damage on the embryo influences early plant development (embryo survival, germination, seedling emergence and performance). We used intact and weevil‐infested seeds of a prevalent Ca...

Mediterranean oak woodlands are currently undergoing considerable anthropogenic changes that globally threaten their long‐term persistence. Restoration efforts via assisted regeneration depend on species traits and type of stress. However, how different sources of stress vary across space (microsites) and time (intra‐ and inter‐annual variation) fo...

Interactions between plants and their root‐associated fungi (RAF) may influence the relative abundance of tree species and determine forest community diversity. Such plant–soil feedbacks in turn depend on the degree to which spatial distance and phylogenetic relatedness of host trees structure pathogen and mutualist communities, but research detail...

Habitat loss and fragmentation, together with related edge effects, are the primary cause of global biodiversity decline. Despite a large amount of research quantifying and demonstrating the degree of these effects, particularly in top predators and their prey, most fragmented patches are lost before their conservation value is recognized. This stu...

Land-cover change in the Osa Peninsula at different years, 1969, 1987, 1998, 2018 (Map Data: Google, US Geological Survey, Landsat / Copernicus, SIO, NOAA, U.S Navy, NGA, GEBCO, LDEO-Columbia, NSF). Lapa Rios Ecolodge went from deforestation to forest recovery after the Nature Preserve was stablished in 1992. In contrast, Playa Sandalo forest cover...

Actions and initiatives for management of Playa Sandalo. (PDF)

Raw camera trap data collected in Lapa Rios Ecolodge Natural Reserve and Playa Sandalo. Included information from all photo events collected by this study (i.e. area, site, GSP location, date, time, species identification, and number of individuals). (CSV)

Rat eradication has become a common conservation intervention in island ecosystems and its effectiveness in protecting native vertebrates is increasingly well documented. Yet, the impacts of rat eradication on plant communities remain poorly understood. Here we compare native and non-native tree and palm seedling abundance before and after eradicat...

Fifteen years of precipitation on Palmyra Atoll. Rainfall on Palmyra Atoll from 2002 to 2017. Survey month and two months prior to the survey period are highlighted (red dots = pre-eradication and blue dots = post-eradication). Horizontal lines indicate average rainfall and one standard deviation. (TIF)

Count of locally rare tree seedling plots. (DOCX)

Interactions between plants and root-associated fungi can affect the assembly, diversity, and relative abundances of tropical plant species. Host-symbiont compatibility and some degree of host specificity are prerequisites for these processes to occur, and these prerequisites may vary with host abundance. However, direct assessments of whether spec...

Embryo damage in seed predation is a common occurrence and has been generally considered equivalent to seed death. We hypothesize that seeds with proportionally larger embryos (radicle plus plumule) provide greater tolerance to seed damage by rodents, allowing successful germination. To test this hypothesis, we examined germination and estimated th...

The decade of the fifties of the twentieth century triggered huge changes in land use and management in ecosystems worldwide, including the iconic Mediterranean ecosystems known as dehesas. In this study, we have quantified the changes in dehesa landscape status within a geographic area of 200,000 km² covering mainly the Spanish dehesa range over t...

Significance The strong focus on species extinctions, a critical aspect of the contemporary pulse of biological extinction, leads to a common misimpression that Earth’s biota is not immediately threatened, just slowly entering an episode of major biodiversity loss. This view overlooks the current trends of population declines and extinctions. Using...

Due to the elusive nature and low densities of wild felids, traditional mark-recapture methods for estimating population size are often insufficient to guide appropriate conservation actions. Furthermore, wildlife ranges are often reduced by ever-expanding urban landscapes, making it difficult to study elusive felids and maintain stable populations...

Understanding the effects of land conversion for livestock grazing on species diversity and functional groups continues to be urgently needed to assess how ranching affects animal assemblages and provide guidelines for managing landscapes under this omnipresent type of land use. Given Neotropical bats' high diversity of feeding habits and flying ab...

Species phenotypic traits affect the interaction patterns and the organization of seed‐dispersal interaction networks. Understanding the relationship between species characteristics and network structure help us understand the assembly of natural communities and how communities function. Here, we examine how species traits may affect the rules lead...

Understanding tree recruitment is crucial to assess species turnover in mixed forests and woodlands, particularly in light of current anthropogenic impact. Here, we investigate whether oak recruitment (density of young oaks) in co-existing deciduous and evergreen oaks is disproportional to the abundance of their corresponding reproductive trees, fa...

Understanding the effects of anthropogenic disturbance on zoonotic disease risk is both a critical conservation objective and a public health priority. Here, we evaluate the effects of multiple forms of anthropogenic disturbance across a precipitation gradient on the abundance of pathogen-infected small mammal hosts in a multi-host, multi-pathogen...

Looking back to move forward The current impacts of humanity on nature are rapid and destructive, but species turnover and change have occurred throughout the history of life. Although there is much debate about the best approaches to take in conservation, ultimately, we need to permit or enhance the resilience of natural systems so that they can c...

In our recent perspective article, we noted that most (approximately 0 percent) terrestrial large carnivore and large herbivore species are now threatened with extinction, and we offered a 13-point declaration designed to promote and guide actions to save these iconic mammalian megafauna (Ripple et al. 2016). Some may worry that a focus on saving m...

Biological invasions are a pervasive and dominant form of anthropogenic disturbance. However, we seldom have the opportunity to evaluate the long-term, indirect, and often slow-moving cascading effects of invasions at the community and ecosystem scale. Here we synthesize the collective knowledge from 10 years of study on the influence of the deep h...

Anthropocene defaunation, the global extinction of faunal species and populations and the decline in abundance of individuals within populations, has been predominantly documented in terrestrial ecosystems, but indicators suggest defaunation has been more severe in freshwater ecosystems. Marine defaunation is in a more incipient stage, yet pronounc...

Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 3...

Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 3...